What is offence coding and why do we do it?

The NZCASS does not ask survey respondents directly about crimes that happened to them, such as ‘Have you been burgled?’ This is because people don’t always know what is legally considered a crime and what isn’t. Legal experts code information collected about an incident (‘offence coding’) to decide whether or not the incident was a crime and what type of crime.

How are offences coded?

The legal experts decide on offence codes using the answers from the victim forms, which include a short description in the respondent’s own words (except for sexual offences). The experts also use answers to other questions throughout the questionnaire.

One NZCASS research objective is to compare the level of reported crime with Police statistics. As such, it’s important that offence coding for NZCASS mirrors the way Police record offences as closely as possible. An exact match with Police recording practice is unlikely given that:

different police officers may make different judgments when deciding:

whether to record an incident as an offence

which category it should be placed in

Police continuously review and refine recording rules, which means some changes to practice have occurred between surveys.

As a general principle, offences in the NZCASS are coded in line with:

current legal theory

current Police recording procedures.

In most cases, these two requirements will be met and there will be no conflict (this means Police recording practice will be in line with the legal theory and definitions).